AP Biology class blog for discussing current research in Biology

Author: actrevationenergy

How Ionizing Radiation Damages Genetic Material and Causes Cancer


All around us there is ionizing radiation. It comes from the sun as Ultraviolet rays, in medical equipment as X-rays or Gamma rays, or even from lightning bolts. But what is Ionizing radiation and why is it considered so dangerous. Ionizing radiation is a form of high energy that removes electrons from materials that it comes into contact with. When ionizing radiation comes into contact with cells, it damages them by either directly breaking the bonds between DNA or by ionizing water. Ionized water creates free radicals that then move around and damage DNA. The damage DNA then leads to cancer, but it has never been discovered what types of cancer ionizing radiation causes. However the Wellcome Trust Sanger Institute has finally been able to identify two types of DNA damage caused by ionizing radiation. From previous studies, it has been revealed that radiation damage on DNA leaves a specific fingerprint. By mapping the DNA damage found in cancer cells that were caused by radiation and comparing them to regular cancer cells, the scientists found two mutational patterns that were common in all forms of radiation induced cancers. The first pattern is a deletion of small DNA bases. The second pattern is called balanced inversions, which is where a middle piece of DNA is cut out and attached back to the end. Balanced inversions are not found naturally and can only be caused by radiation damage. From this discovery, scientists hope to be able to identify radiation caused tumors against regular tumors. This may help in finding a specific and more effective cure for the different kinds.

The Effect of Malnutrition on the Gut Microbiome

Malnutrition is a brutal issue that has plagued the world for years and affects communities that can’t afford to help themselves. Recently there has been a link between malnutrition and the condition of the gut microbiome. The gut microbiome describes the microbiota, micro organisms, that live in the digestive tract and have  David Relman, a microbiologist at Stanford University School of Medicine, explained the two studies that believe that tailoring a specific diet for people suffering from malnutrition can improve their gut microbiomes and subsequently improve their health.  Tahmeed Ahmed, director of nutrition research at the International Centre for Diarrhoeal Disease Research, and Jeffrey Gordon, a gastroenterologist and microbiome researcher at Washington University, started two studies into how malnutrition effects the microbiome. After observing healthy and malnutrition babies grow into toddlers, the two noticed how malnutrition causes the micro biome to remain immature and stay in the same state as a babies instead of maturing like a normal person’s. The two then conducted studies on mice looking for changes in mice with malnutrition and found that the mice had weaker bones, less muscle mass, and impaired metabolism. From these results the two scientists have deduced certain foods that should be given to help fix immature mircobiomes. Current food in care packages do not have these necessary requirements to fix microbiomes. They contain food like rice and powedered milk, but chickpea, soy, peanut flours, and bananas have been proven to help the microbiome and should be added into care packages. By targeting the microbiome in malnutrition, these scientists have been able to reverse the negative affects and force the body to catch up on lost growth. The leading obstacle with this discovery is that malnutrition effects the poor, who do not have access to the healthier kinds of food required to repair their crippled microbiomes.

Giraffes, Giraffes, Giraffes, and More Giraffes


On the left is the Southern giraffe, while on the right is the Northern giraffe. They look the same but are genetically different.

Previously there was thought to be only one giraffe species, but recently with the help of genetic testing there are now four confirmed giraffe species. To make this amazing discovery, Scientists from the Senckenberg and the Giraffe Conservation Foundation utilized several nuclear marking genes on over 100 giraffes and analyzed the genetic relationship between all major species in the wild. The Giraffe Conservation Foundation collected more than 100 biopsy samples over the past decades from all areas of Africa, including war torn regions. They then sent the samples to the Senckenberg Biodiversity and Climate Research Centre for analysis. The nuclear genes, which are genes found in the nucleus of Eukaryotes, were different enough in each group that it reveals how different species do not mate with each other. The four distinct species that were discovered are the southern giraffe, masai giraffe, reticulated giraffe, and northern giraffe. Besides demonstrating four groups, the scientists concluded from the data that some sub-species are in fact the same. The discovery highlights the need for greater conservation efforts for the overall giraffe species. While giraffes are already close to extinction, the idea that there are now four species exacerbates the issue as they are even closer to losing each diverse group.  With the giraffe species declining over 40% in the last 30 years to the point of only 68,000 of them left in the wild.

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